The goal of the Research Support Core is to provide core research support services and resources to all Center investigators. These services and resources are divided into five subcores: The Analytic and Data Services Subcore will provide statistical consultation and analysis programming for newer statistical techniques that are particularly germane to studying the trajectory of chronic illness and the impact of interventions over time (mixed models, longitudinal analysis using structural equation modeling, SUDAAN, etc.). In-depth seminars will also be offered in these statistical techniques. The Subcore will also provide data management for the pilot/feasibility studies and consult with other Center investigators in this area. The Methods for Studying Vulnerable Populations Subcore will provide methodological consultation to investigators proposing new studies on vulnerable populations; provide psychometric consultation for the design or revision of instrumentation for use in vulnerable populations; establish a methods and instrumentation library for protocols and instruments that have been found to be appropriate for specific vulnerable groups; provide an expert forum for current Center investigators to discuss methodological issues that arise during the course of ongoing studies; provide a mechanism by which individuals from within the identified vulnerable groups can inform and guide our studies; and work collectively to explore and develop new methods for appropriately studying vulnerable people. The goals of the Biobehavioral Support Subcore are to increase the use of minimally invasive biobehavioral measurement of dynamic and cumulative latent variables in chronic illness, to develop and enhance biobehavioral measurement methods for use with chronically ill populations, and to enhance the training and education of investigators and students in biobehavioral measurement techniques. The Cost Analysis Subcore will make available expert consultation and seminars on costing, cost/effectiveness, and benefit/cost analysis to assist investigators with the design and operationalization of methods to evaluate the cost effectiveness of their interventions. The General Research Support Services Subcore will provide secretarial and research assistant services to the pilot/feasibility studies and general research support services to all Center investigators through the School's Research Support Center.